GAZA, Nov 16 (Reuters) - Egypt opened a tiny window to
emergency peace diplomacy in Gaza on Friday, but hopes for even
a brief ceasefire while its prime minister was inside the
bombarded enclave to talk to leaders of the Islamist Hamas
movement were immediately dashed.

Prime Minister Hisham Kandil visited the Gaza Strip on
Friday officially to show solidarity with the Palestinian people
after two days of relentless attacks by Israeli warplanes
determined to end militant rocket fire at Israel.

But a Palestinian official close to Egypt's mediators told
Reuters that Kandil's visit, which included members of Cairo's
secret service, "was the beginning of a process to explore the
possibility of reaching a truce. It is early to speak of any
details or of how things will evolve".

Israel undertook to cease fire during the visit if Hamas did
too. But it said rockets fired from Gaza had hit several sites
in southern Israel as he was in the enclave.

According to a Hamas source, the Israeli air force launched
an attack on the house of Hamas's commander for southern Gaza
which resulted in the death of two civilians, one a child.

But Israel's military strongly denied carrying out any
attacks from the time Kandil entered Gaza, and accused Hamas of
violating the three-hour deal. "Israel has not attacked in Gaza
for the past two hours," a spokesman said.

"Even though about 50 rockets have fallen in Israel over the
past two hours, we chose not to attack in Gaza due to the visit
of the Egyptian prime minister. Hamas is lying and reporting
otherwise," the army said in a Twitter message.

Kandil said: "Egypt will spare no effort ... to stop the
aggression and to achieve a truce."

At a Gaza hospital he saw the bloodied body of a child. He
left the Gaza Strip after meeting with Hamas leader Ismail
Haniyeh, the enclave's prime minister.

Palestinian medics said two people were killed in the
disputed explosion at the house, one of them a child. It raised
the Palestinian death toll since Wednesday to 21. Three Israelis
were killed by a rocket on Thursday.

Air raid sirens wailed over Tel Aviv on Thursday evening,
sending residents rushing for shelter and two long-range rockets
exploded just south of the metropolis. The location of the
impacts was not disclosed.

They exploded harmlessly, police said. But they have shaken
the 40 percent of Israelis who, until now, lived in safety
beyond range of the southern rocket zone.

Israel has started drafting 16,000 reserve troops, in what
could be a precursor to invasion.

The 21 Palestinian dead include eight militants and 13
civilians, among them seven children and a pregnant woman. A
Hamas rocket killed three Israeli civilians a town north of
Gaza, men and women in their 30s.

The last Gaza war, a lopsided three-week long Israeli air
blitz and ground invasion over the New Year period of 2008-2009
aimed at ending repeated rocket attacks, left more than 1,400
Palestinians dead, mostly civilian, and killed 13 Israelis.

THE MESSAGE

"If Hamas says it understands the message and commits to a
long ceasefire, via the Egyptians or anyone else, this is what
we want. We want quiet in the south and a stronger deterrence,"
Israeli vice prime minister Moshe Yaalon said.

"The Egyptians have been a pipeline for passing messages.
Hamas always turns (to them) to request a ceasefire. We are in
contact with the Egyptian defence ministry. And it could be a
channel in which a ceasefire is reached," he told Israeli radio.

At the same time, there were signs of possible preparations
for a ground assault on Gaza. In pre-dawn strikes, warplanes
bombed open land along the border zone with Israel, in what
could be a softening-up stage to clear the way for tanks.

Self-propelled heavy artillery was seen near the border.

The United States has asked countries that have contact with
Hamas to urge the Islamist movement to stop its recent rocket
attacks from Gaza, a White House adviser said.

"We've ... urged those that have a degree of influence with
Hamas, such as Turkey and Egypt and some of our European
partners, to use that influence to urge Hamas to de-escalate,"
Ben Rhodes, deputy national security adviser, said in a
conference call with reporters.

U.S. Defense Secretary Leon Panetta said in an interview
with Voice of America: "I understand the reasons Israel is doing
what they're doing. They've been the target of missiles coming
in from Gaza ... ."

EGYPT ON THE SPOT

The Gaza conflagration has stoked the flames of a Middle
East ablaze with two years of Arab revolution and a civil war in
Syria that threatens to engulf the whole region.

Hamas refuses to recognise Israel's right to exist. By
contrast, Palestinian President Mahmoud Abbas, who rules in the
nearby West Bank, does recognise Israel, but peace talks between
the two sides have been frozen since 2010.

Abbas's supporters say they will push ahead with their plan
to become an "observer state" rather than a mere "entity" at the
United Nations later this month.

Despite fierce opposition from both Israel and the United
States, they look certain to win the vote in the General
Assembly, where they have a built a majority of supporters.

Egypt's new Islamist president, Mohamed Mursi, viewed by
Hamas as a protector, led a chorus of denunciation of the
Israeli strikes by allies of the Palestinians.

Mursi faces domestic pressure to act tough. But Egypt gets
$1.3 billion a year in U.S. military aid and looks to Washington
for help with its ailing economy, constraining Mursi despite his
need to show Egyptians that his policies differ from those of
his U.S.-backed predecessor, Hosni Mubarak.

Hamas leader Ismail Haniyeh on Thursday urged Egypt to do
more to help the Palestinians.

"We call upon the brothers in Egypt to take the measures
that will deter this enemy," the Hamas prime minister said.

The appeal poses a test of Mursi's commitment to Egypt's
1979 peace treaty with Israel, which the West views as the
bedrock of Middle East peace.

The Muslim Brotherhood, which brought Mursi to power in an
election after the downfall of pro-Western Hosni Mubarak, has
called for a "Day of Rage" in Arab capitals on Friday. The
Brotherhood is seen as the spiritual mentor of Hamas.

The Israel Defence Forces (IDF) said they had targeted over
450 "terror activity sites" in the Gaza Strip since Operation
Pillar of Defence began with the assassination of Hamas' top
military commander on Wednesday by an Israeli missile.

"The sites that were targeted were positively identified by
precise intelligence over the course of months," it said. "The
Gaza strip has been turned into a frontal base for Iran, forcing
Israeli citizens to live under unbearable circumstances."

Israeli bombing has not yet reached the saturation level
seen before it last invaded Gaza in the first days of 2009, when
armoured bulldozers and tanks flattened whole districts of the
crowded enclave to make way for fire bases and open routes for
infantry.